Modeling Combined Safety and Operational Effect of Detection Solution to Signal Dilemma Zone Problems

Yellow light dilemma zone is one of the critical factors that possibly cause rear-end and right-angle crashes at high speed signalized intersections. It is an ideal objective of practical solutions to minimize the dilemma hazard while maximizing the operational efficiency. This study is intended to quantify the concerned objective by defining the combined cost for dilemma hazard and delay. A microscopic simulation based approach is applied to compute the dilemma hazard of each approaching vehicle. The operational efficiency is assessed by the overall intersection delay. An optimization framework is designed to minimize the combined cost for dilemma hazard and delay. An optimal detector configuration is obtained and evaluated via comparison with SSITE configuration, which is recommended by FHWA. The evaluation result concludes the superiority of the optimal detector configuration in terms of better safety and operational performances, as well as less combined cost for dilemma hazard and delay.